I'm sorry you are going through this, Stewy. I'm assuming you're in the UK. If so and if your name is on the title deed, I wouldn't have thought you need to go anywhere. If you own the property jointly and have a joint mortgage, it could get messy financially. If the relationship is really breaking down irretrievably, you need to come to an agreement with her about what to do with the mortgage (assuming there is one) and the property.
Legals aside, from a moral standpoint, I also don't see why you should be the one to leave.